The Fibonacci sequence is a list of positive integers denoted
F(1), F(2), F(3), ... where
F(1) = 1, F(2) = 1
F(n+2) = F(n) + F(n+1), for n³3
So the first 12 Fibonacci numbers are
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144
Here is a simple problem that illustrates one way Fibonacci numbers pop up.
You buy a female calf and she produces her first shecalf at age two years
and after that produces another single shecalf every year. Moreover, each new shecalf performs the same way.
How many shecalves are there after 12 years, assuming none die?

The following kinds of flowers have numbers of petals as indicated. Some are
precise about their number of petals and some are averages.
 3 petals: lily, iris.
Often lilies have 6 petals formed from two sets of 3.
 5 petals: buttercup, wild rose, larkspur, columbine (aquilegia).
The humble buttercup has been bred into a multipetalled form.
 8 petals: delphiniums
 13 petals: ragwort, corn marigold, cineraria,
 21 petals: aster, blackeyed susan, chicory
 34 petals: plantain, pyrethrum
 55, 89 petals: michaelmas daisies, the asteraceae family
